well I found out that transaction managers/datasources aren't remotely accesible... You need register your jndi as global jndi and acces it by http or jnp:
http://www.engfers.com/2008/08/07/exposing_accessing-jboss-jndi-objects_datasources-from-an-external-jvm/
and if it comes to transaction managers, I am not sure if it is possible at all:
"While it does support propagating transaction contexts with remote calls, it does not support propagating transaction contexts to other virtual machines, so all transactional work must be done in the same virtual machine as the JBoss server."
from:
http://docs.jboss.org/jbossas/jboss4guide/r1/html/ch4.chapt.html
after all I gave up... I am now writing web application which I am going to deploy on jboss and try to connect to it via rmi or something like that.
Good luck to you
btw. if you manage to do that after all please let me know how ;)